This invention concerns a flashing light warning apparatus of a type having a voltage source, a main blocking, or isolating, transformer, a flash tube, an ignition device, two storage condensers, and an electrical switching apparatus.
Such a flashing light warning apparatus is described in U.S. Pat. No. 3,644,818 to Paget as having a voltage source, a main blocking (or gate, or isolation) transformer, a flash tube, an ignition device (or circuit) two storage condensers, and an electrical switching device. The electrical switching device is, in that case, arranged in series with one of the two storage condensers. When the electrical switching device is closed, both of the storage condensers are charged, or energized, to the same storage voltage. When the electrical switching device is open, the first storage condenser is charged somewhat more slowly than the second storage condenser through a resistor. By this means, the electrical energy provided to the flash tube, and thereby the light flash energy, should be influenced in dependence upon a switched position of the switching device such that with an open switching device a reduced light energy is released by the flash tube.
A disadvantage of the known light flash warning apparatus is, however, that it cannot produce light flashes with such reduced light energy that they do not disturb operation of, for example, airplanes utilizing night vision devices, because, despite the resistor which should effect a slower charging of the first condenser, this one, along with the second condenser, will be charged and upon ignition of the flash tube will be discharged. Light flashes produced in this manner display a light energy which lead to a blinding of a pilot employing night vision apparatus, also known as night vision goggles (NVG), with a surer operation not being possible.
This invention has the purpose of providing a flashing light warning apparatus which can be produced in an uncomplicated and cost effective manner and which, while dependably producing light flashes, makes possible a changing of light energy between a day flash and at least one night flash, in which the night flash achieves a light level which from afar is only recognizable with night vision apparatus.